He is believed to have died, aged 49, in a fire at his residence north of Paris on 3 September 1914, whilst defending his estate from Germansoldiers.

Several unpublished works were lost in the fire, including the orchestralscore to the operaGuercoeur, but this was later reconstructed by Magnard's friend and colleague Guy Ropartz, and staged at the Paris Opéra in 1931.